Gases emitted by two volcanos Poás (foreground) and Turrialba (farthest) increased the amount of sulfur dioxide in the environment. In the photo, captured this Thursday at 6:40 a.m. from an airplane, you can also see the Barva and Irazú volcanoes. (Photo by Laura Barboza Rodríguez)

Q COSTA RICA -The Poas volcano eruptions are triggering air pollution in the Greater Metropolitan Area (GAM) of San Jose at levels that exceed the maximum values ​​allowed by the World Health Organization (WHO).

This means that the residents of GAM that includes the capital city (San Jose) and the cities of Alajuela, Cartago and Heredia are breathing high amounts of sulfur, carbon dioxide and sometimes ash particles that can affect their health.

The pollution levels were confirmed from measurements made by the Volcanological and Seismological Observatory of Costa Rica (Ovsicori) on Thursday, April 13 at 2:40 pm, almost an hour before the strongest eruption that day and 3:40 pm.

The air quality at the Hatillo (south side of San Jose) monitoring station recorded an average sulfur dioxide concentration of 81 parts per billion (ppb), with a maximum peak of 99.1 ppb, which exceeds the WHO limit of 75 ppb.

According to Jorge Herrera, coordinator of the environmental analysis laboratory of the Universidad Nacional (UNA) – National University, the Poás gas emission is modifying the air quality in the GAM, which was already compromised due to the eruptions of the Turrialba volcano, as well as contamination of the industries and vehicles.

Other monitoring stations located in Coronado (San Jose) and Alto de Ochomogo (Cartago) also had a high gas concentration that day, explained Herrera.

Measurements of sulfur dioxide and carbon dioxide at the edge of the Poas volcano active crater, between April 10 and 14, are the highest recorded at the volcano, revealed the UNA.

The monitoring equipment was destroyed by subsequent eruptions.

Scientists interpret these values ​​ss the presence of fresh magna very close to the surface.

All these data are consistent with the detection of a sulfur dioxide cloud over the central region of Costa Rica that was identified by the NASA AURA satellite during the days of highest concentrations.

Sulfur dioxide is a colorless gas with a penetrating, choking odor that can damage the respiratory system with only a short exposure to high concentrations.

Children, the elderly and people with asthma are particularly sensitive to these emanations that can cause health problems.

Herrera explained that the emissions generated by the two volcanos (Poas and Turrialba) are natural processes, but are a source of pollution.

The expert added that today, Friday, the Ovsicori and the Ministry of Health are going to erect a measuring station in Fraijanes and Sabanilla (Alajuela) and soon in Grecia, to transmit real-time air quality.

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